Unraveling the fabric of space-time with Dr. Ian O'Neill

Category Archives: Physics

Only last month I recorded a DNews video about the awesome possibilities of the “Cold Spot” that sits ominously in the cosmic microwave background (CMB) anisotropy maps (anisotropies = teenie tiny temperature variations in the CMB).

I still hold onto the hope that this anomalous low temperature region is being caused by a neighboring parallel universe squishing up against our own. But evidence is mounting for there actually being a vast low density region — known as a “supervoid” — between us and that Cold Spot.

And that’s crappy news for my dreams of cosmologists finding bona fide observational clues of the multiverse hypothesis any time soon. The Cold Spot could just be the frigid fingerprint of this supervoid etched into our observations of the CMB.

But as this supervoid could be as wide as 1.8 billion light-years, this discovery is still crazy cool — the supervoid could be the newest candidate for the largest structure ever discovered in the universe. Suck it, Sloan Great Wall.

A segment of the Large Hadron Collider’s super-cooled electromagnets. Credit: CERN/LHC

After a 2 year hiatus for a significant upgrade, the Large Hadron Collider is being switched back on and, early on Sunday, the world’s most powerful particle accelerator saw the first circulation of protons around its 27 kilometer ring of superconducting electromagnets.

This is awesome news, especially as there was a minor electrical short last week that could have derailed this momentous occasion for weeks, or maybe months. In one of magnet segments, a metallic piece of debris from the upgrade work had become jammed in a diode box, triggering the short. Manual removal of the debris would have forced a lengthy warm up and then cool down back to cryogenic temperatures, but CERN engineers were able to find a quick fix — by passing an electrical current through the problem circuit the tiny piece of debris was burnt away, no warm-up required.

With this small hiccup out of the way, the complex task of circulating protons around the LHC began this weekend, resulting in two sparsely populated beams of protons speeding around the LHC in opposite directions. So far, so good, but the particle accelerator is far from being ready to recommence particle collisions.

“Bringing the LHC back on, from a complete shutdown to doing physics, is not a question of pushing a button and away you go,” Paul Collier, head of beams at CERN, told Nature News.

Sure, the LHC is circulating protons, but it is far from restarting high-energy collisions. In fact, over the coming weeks and months, engineers will be tuning the machine to finely collimate the counter-rotating beams of protons and gradually ramping-up their speed. The first collisions aren’t expected to begin until June at the earliest.

But seeing protons pump around the LHC for the first time since 2013 is an awesome sign that all the high-energy plumbing is in place and the electrical backbone of the accelerator appears to be working in synergy with the massive magnetic hardware.

Over the next 8 weeks, engineers will turn on the LHC’s acceleration systems, boosting the beam energy from 450 GeV to 6.5 TeV, gradually focusing the beams in preparation for the first collisions.

According to Nature, the re-started LHC will slam 1 billion pairs of protons together every second inside the various detectors dotted around the accelerator ring with a collision energy of 13 TeV, boosting the LHC’s energy into a whole new regime. During the LHC’s first run, the maximum energy recorded was 8 TeV.

This makes for a curious time in cutting-edge particle physics.

Before the LHC was fully commissioned in 2008, its clear task was to track down, discover and characterize the Higgs boson, the last remaining piece of the Standard Model. Having achieved the Higgs discovery in 2012 — resulting in the 2013 Nobel Prize being awarded to Peter Higgs and François Englert — physicists have been combing through the reams of data to understand the new particle’s characteristics. Although a lot still needs to be learnt about the famous boson that endows all matter with mass, Run 2 of the LHC has a rather vague mission. But “vague” certainly doesn’t mean dull, we could be entering into a new era of physics discovery.

I always imagine that powering up the LHC is like this… completely inaccurate, mind you.

We’ve never seen collision energies this high before, and with the Standard Model all but tied up, physicists are on the lookout for phenomena with an “exotic” flavor. Exotic, in this case, means the production of quantum effects that cannot be easily explained or may be driven by mechanics that have, until now, been considered pure speculation.

Personally, I’m excited that the LHC may generate a signature that we cannot explain. I’m also trilled by the possibility of micro-black holes, the discovery of dark matter particles, potential hints of supersymmetry and quantum gravity. But I’m doubly-thrilled by the prospect of something popping out of the collision debris that doesn’t make any sense.

As the LHC will now slam protons (and, later, ions) at energies nearly double of what it was previously capable of, we are in uncharted territory. Physicists are recreating the conditions of the Big Bang, condensing primordial particles and forces from the concentrated energy of colliding beams of charged particles. So far, after only 7 years since the LHC was first powered up, it has already confirmed the existence of a Standard Model Higgs boson. So now, without a single ultimate goal, the LHC will do what physics does best, discovery-driven science that could answer many quantum mysteries and, hopefully, create many more.

This month is Global Astronomy Month (GAM2013) organized by my friends Astronomers Without Borders (AWB). There is a whole host of events going on right this moment to boost astronomy throughout the international community, and as a part of GAM2013, AWB are hosting daily blogs from guest astronomers, writers, physicists and others with a background in space. Today (April 11) was my turn, so I wrote a blog about the fascinating first results to be announced on the International Space Station instrument the Alpha Magnetic Spectrometer — or AMS for short.

Although the AMS’ most recent findings suggest positrons with a signature energy indicative of the annihilation of dark matter — particularly hypothetical weakly interaction massive particles (WIMPS) — it isn’t final proof of dark matter (despite what the tabloid press might’ve told you). But still, it’s exciting and another component of our enduring search for 95.1% of the mass-energy of the universe that is locked in the mysterious and perplexing dark matter and dark energy.

“Intercontinental travel will never happen. The nearest shore is thousands of miles away. This means that even if we had the ability to row five miles per day from our little island, it would take years to get there!

To rub (sea) salt into the wound, the nearest shoreline is probably not a place we’d want to visit anyway. We’ve heard that beasts of unimaginable horror lurk over the horizon. Even worse, what if that undiscovered country is a desert-like place, or a disease-ridden tropic? Perhaps water doesn’t even flow as a liquid! Imagine trying to live in a land covered with ice. What a thought!

To put it bluntly, our little island is quarantined from the rest of the world. But it’s not a quarantine where we are locked inside an impenetrable room, we’re quarantined by a mind-bogglingly vast expanse of ocean. We live here with only a rowing boat for transportation — you can do some laps around the island in that rowing boat, but that’s all.

Forget about it. Don’t look at those distant shores and think that some day we’ll be able to build an engine for that rowing boat. A little outboard motor wouldn’t get you very far — you’d likely run out of gas before the island is out of sight! Heck, you’ll probably starve before then anyway.

Just go home. Why are you still planning on building a big boat — that sci-fi notion of a metal-hulled “ship” no less! — when you should be worrying more about your little island? We have problems here! Our resources are dwindling, people are starving! Your dreams mean nothing in our everyday lives.”

There’s no better method to understand how something works than to build it yourself. Although computer simulations can help you avoid blowing up a city block when trying to understand the physics behind a supernova, it’s sometimes just nice to physically model space phenomena in the lab.

So, two Caltech researchers have done just that in an attempt to understand a beautifully elegant, yet frightfully violent, solar phenomenon: coronal loops. These loops of magnetism and plasma dominate the lower corona and are particularly visible during periods of intense solar activity (like, now). Although they may look nice and decorative from a distance, these loops are wonderfully dynamic and are often the sites of some of the most energetic eruptions in our Solar System. Coronal loops spawn solar flares and solar flares can really mess with our hi-tech civilization.

A coronal loop as seen by NASA’s Transition Region and Coronal Explorer (TRACE). Credit: NASA

In an attempt to understand the large-scale dynamics of a coronal loop, Paul Bellan, professor of applied physics at Caltech, and graduate student Eve Stenson built a dinky “coronal loop” of their own (pictured top). Inside a vacuum chamber, the duo hooked up an electromagnet (to create the magnetic “loop”) and then injected hydrogen and nitrogen gas into the two “footpoints” of the loop. Then, they zapped the whole thing with a high-voltage current and voila! a plasma loop — a coronal loop analog — was born.

Although coronal loops on the sun can last hours or even days, this lab-made plasma loop lasted a fraction of a second. But by using a high-speed camera and color filters, the researchers were able to observe the rapid expansion of the magnetic loop and watch the plasma race from one footpoint to the other. Interestingly, the two types of plasma flowed in opposite directions, passing through each other.

The simulation was over in a flash, but they were able to deduce some of the physics behind their plasma loop: “One force expands the arch radius and so lengthens the loop while the other continuously injects plasma from both ends into the loop,” Bellan explained. “This latter force injects just the right amount of plasma to keep the density in the loop constant as it lengthens.” It is hoped that experiments like these will ultimately aid the development of space weather models — after all, it would be useful if we could deduce which coronal loops are ripe to erupt while others live out a quiescent existence.

It’s practical experiments like these that excite me. During my PhD research, my research group simulated steady-state coronal loops in the hope of explaining some of the characteristics of these fascinating solar structures. Of particular interest was to understand how magnetohydrodynamic waves interact with the plasma contained within the huge loops of magnetism. But all my research was based on lines of code to simulate our best ideas on the physical mechanisms at work inside these loops. Although modelling space phenomena is a critical component of science, it’s nice to compare results with experiments that aim to create analogs of large-scale phenomena.

The next test for Bellan and Stenson is to create two plasma loops inside their vacuum chamber to see how they interact. It would be awesome to see if they can initiate reconnection between the loops to see how the plasma contained within reacts. That is, after all, the fundamental trigger of explosive events on the Sun.

We have reality TV stars whose only talent is to shock and annoy, and yet inexplicably have millions of adoring fans. We also have sports superstars who get paid tens of millions of dollars to play a game they love, and yet they still get elevated to God-like status.

And then there’s Professor Peter Higgs, arguably the biggest science superstar of recent years.

The 83-year-old retired theoretical physicist was one of six scientists who, in the 1960s, assembled the framework behind the Higgs boson — the almost-unequivocally-discovered gauge particle that is theorized to carry the Higgs field, thereby endowing matter with mass. The theory behind the Higgs boson and all the high-energy physics experiments pursuing its existence culminated in a grand CERN announcement from Geneva, Switzerland, on Wednesday. With obvious emotion and nerves, lead scientist of the Large Hadron Collider’s CMS detector Joe Incandela announced what we’ve all been impatiently waiting for: “We have observed a new boson.”

So, we now have evidence for the existence of the Higgs boson — or a Higgs boson — to a high degree of statistical certainty, ultimately providing observational evidence for a critical piece of the Standard Model. This story began half a century ago with Prof. Higgs’ theoretical team, and it culminated on July 4, 2012, when results from a $10 billion particle accelerator were announced.

After the historic events of the last few days, one would think Peter Higgs would have been at least treated to a First Class flight back to his home in Scotland. But true to form, Higgs had other ideas:

Later, Higgs’s friend and colleague Alan Walker recounted the low-key celebration they held after learning of the breakthrough, one of the most important scientific discoveries of recent years.

Walker said he and Higgs were flying home from CERN in Geneva this week on budget airline easyJet when he offered Higgs a glass of Prosecco sparkling wine so they could toast the discovery.

Higgs replied: “‘I’d rather have a beer’ and popped a can of London Pride,” Walker said.

In a world where “celebrities” are hailed as superhuman, to hear that potential Nobel Prize candidate Peter Higgs took a budget airline home, after history had been made, typifies the humble nature of a great scientist and puts the world of celebrity to shame. Money and fame matters little to the people who are unraveling the fabric of the Universe.

On a different (yet related) note, Motherboard interviewed people on the streets of Brooklyn and asked them if they knew what the Higgs boson is. Most had never heard of it, let alone understood it (which, let’s face it, isn’t a surprise — many science communicators still have problems explaining the Higgs mechanism). But I wonder if the same group of people were asked if they knew what a “Snookie” was; I’m guessing they’d have no problem answering.

People may not read the news, but they sure have an innate knowledge of who’s in the gossip columns.

Yes, the Higgs boson has been discovered… or, to put it more accurately, something that looks like a Higgs boson has been discovered. But is it a Higgs boson? There’s a very high probability that it is, but in the world where theory meets high-energy physics, it pays to be completely sure about what you’re looking at.

But for the ATLAS and CMS collaborations at the Large Hadron Collider in CERN, near Geneva, Switzerland, who held a rapturous conference at CERN and in Australia this morning, they’re pretty damned sure they are looking at a bona fide Higgs boson discovery.

“We have observed a new boson,” said CMS lead scientist Joe Incandela.

“We observe in our data clear signs of a new particle, at the level of five sigma, in the mass region around 126 GeV,” confirmed ATLAS lead scientist Fabiola Gianotti.

“I think we have it,” said CERN Director-General Rolf Heuer. “We have discovered a particle that is consistent with a Higgs boson.”

Why all the certainty? Well, it all comes down to statistics, and all the statistics seem to show a defined “bump” in the CMS and ATLAS data around the mass-energy of 125-126 GeV/c2 — to a statistical certainty of 4.9 and 5 sigma. 125-126 GeV/c2 just so happens to be one of the theorized masses of a Higgs boson — placing the Higgs’ mass at 133 times that of a proton. This particular boson is therefore the most massive boson ever detected.